Gyro caging device



Jan 9, 1945 s. GABRIELsoN GYRO CAGING DEVICE Filed Deo. 27, 1945 2 Sheets-Sheet l IIIIlI-IIIIIIH Invemcrf; Samuel Gabr'elson,

Hisl ttorneg.

Jan. 9, 1945. s. GABRxEL'soN GYRO CAGING DEVIVCE l rFiled Dee. 27 1943 2 sheeisheet 2 Inventor: Samuel Gabrielson,

h Patented Jan. 9,1945

GYRO CAGING DEVICE Samuel Gabrielson, South Lynnfield, Mass., as-

signor to General Electric Company, a corporation of New York Application December 27, 1943, Serial No. 515,843

(Cl. M

5 Claims.

My invention relates to improvements in caging devices for gyro instruments. Gyros are used on movable objects, such as airplanes, asbasic positioning or reference orientingvdevicesn Occasionally it isdesirable to bring anaxis or axes of the gyro in alignment with anaxis or axes of the airplane, and this is called caging the gyro. This may be desirable previous to violent airplane maneuvers to protect the gyro, or it may be desirable from time to time due to drift of the gyro from correct position. The caging device described is suitable for caging a gyro with respect to'two axes at right angles to each other, and is described as applied to an artificial horizon gyro used on airplanes.` Among the objects of my invention is to provide a caging device which may be easily attached to or removed from a gyro, to provide a' caging device which is not likely to be jarred `from a caging position by vibration,-

and to provide a caging device which when moved to caging position does so gradually without shock on the bearings of the gyro.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appendedhereto. For a better understanding of my invention reference is made in the following description to the accompanying drawings in which Fig. 1 represents a side view partially in section of an articial horizon gyro enclosed in a cylindrical casing and to which my caging device has been applied; Fig. 2 represents a somewhat exploded view of a caging head embodying my invention; Fig. 3 represents some of airplane on which it is mounted. The instrument is provided with certain indicators which the pilot observes as required by looking at the back faceof the instrument. One of such indicators is a pointer Il secured to a circular mask VI 8 which in turn is secured at its center to a shaft which extends through the bearing at I5 from gimbal ring I2. As gimbal ring I2 rotates relative to the casing 'about its axis through bearings I5 and I6, mask I8 and pointer I'I also rotate relative to the casing structure and theI pointer I 'I indicates relative toa scale at I9 the angle of bank of the airplane. Another A indicator is a horizontal bar at 2U which extends horizontally in the principal parts of my caging device in caging position with respect to the caging pins of an arltiiicial horizon gyro; and Fig. 4 indicates the mainoperating portions of the caging device in` different operating positions.A I

In Fig. 1, I have represented suiicient of the construction of an artificial horizon gyro to illustrate how my caging device is applied thereto. Ten I Il) may represent the stator bearing frame and I I a portion of the rotor of gyro, the spin axis of which is normally .vertical as represented in4 nions for gimbal ring I2 are at I 5 and I6. Supporting plate I3 is called the front plate because the right-hand end of the instrument as pictured in Fig. 1 extends toward the front of the The bearings or trunfront oi mask I8 from a skeleton lever 2| which is pivoted to gimbal ring I2 on a normally horizontal axis at 3I. The horizontal bar 20 thus ro.. tates from an apparently horizontal position with rotation of the gimbal ring I2 on its axis relative to frame 9. Between pivot 3I and the horizontal bar 2l), lever 2l has a slotted guide 22 into which a pin 23 extends from the gyro stator` IU. Pin 23 is displaced to the right of the axis' II of the gyro stator and thus acts as a crank.` Gimbal ring I2 has an arc-shaped opening 24' through which the pin 23 extends. I

Hence, a tilting movement of the gyro stator I 0 about axis I I moves lever 2I up or down about its pivot 3l, thereby moving the horizontal bar 20 up or down relative to the center'ofmask I8. The

spin axis ofthe gyro ordinarily maintains a true vertical position, and the casing tips Vabout the two axes with bank and pitch of the airplane so that the horizontal bar 20 changes position in the dial opening, moving up when Vthe ship. is climbing and tilting with respect to a horizontal index 25 when the airplane banks. The pilot byv observing these indications thus obtains a true indication of the orientation of his plane relative t0 the horizon, and the instrument is thus called an articial horizon gyro. Ihe details of such an instrument are not features of the present inven` tion, but the brief explanation of the general structure and operation of such an instrument is helpful to an understanding of the caging device now to be described.

When the airplane is in level flight, neither climbing nor diving nor in a bank, and the gyro is properly oriented in true position, the positions of the indicator parts are as represented in Fig. 1. This may be called the central position oi the parts. One purpose of the caging device is to bring the gyro spin axis to a true vertical position if it is not in such position when the ship is in level Hight. Another purpose' of the caging depositions vice is to lock the ,gyro in fixed relation tothe instrument framework during violent airplane ma.- n'euvers in order to prevent damage tothe in' strument.

The cagingdevice employed is pictured separately in Fig.. 2 and is shown mounted in place on the instrument in Fig. l. These illustrations represent thecaging device in open or noncaging position, and in Fig. 2 the caging jaw members 26 and 2,1 and their hollow bearing supporting structure are shown moved away from the head or supporting plate. 28 for better illustration. When properly assembled the screws 29 enter holes 30 `and screw into threaded bushings 32, rigidly holding bearing plate 33 against bushings 32. The bearing vfor jaw arms 26 and 2,1 comprises a hollow bushing 34 firmly staked in plate 33 .and with an extended head supporting the forward face of arm 26 as shown in Fig. 1 at 35. The axis of rotation of' such jaw arms coincides with the axis of rotation of the gimbal ring l2.

The jaws 26 and 21 are rotated about the bearing' at 34 by means of crank pins 36 and 31 which enter generally radial, but somewhat crooked,slots 38 and 39 in the radiallyextending portions of the jaw members 26 and 21. Pins l36 'and'31 extend from crank arms 40 and 4| fixed to` the sides of gear wheels 42 and 43 rotatively mounted on bearing studs 44 and 45 staked into the head plate 28. The peripheries orf gears 42 and 43 mesh with each other and are of the same size so that when gear 43 is .turned counterclockwise as viewed in Fig. 2, the gears rotate in opposite directions and move their crankr arms towards caging 'position at the same rate. Jaw member 26 moves clockwise and jaw member 2.1 moves counterclock- .wise at the same rate toward closed or caging position. The closed position is shown in Fig. 3 and in full lines in Fig. 4. 'I'he axes of rotation of the crank arms 40 and 4| are so positioned relative to theaxis of rotation of the jaw members 26 and 21 that the J'aw members rotate about 100 degrees and the gears 42 and 43 rotate about 180 degrees in moving from open to closed In Fig. 4 open, intermediate, and closed positions, of the jaw members are represented, the corresponding positions of jaw member 26 being so marked. It is seen that in this movement of the jaws from open to closedy positions, the pins 36 and 31 first move outwardly and then inwardly in their slotsk 38 and 39, the pins being near the outer ends vf the slots in the central intermediate positions.

In order to prevent interference between the two jaw members when approaching near to the closed positions, the portion 46 of jaw member 21 has Va reduced radius as compared to jaw member 26 asbest shown in Fig. 3. Such reduced radius .portion 46 of jaw member 21 extends only to .an offset at. 41, so that the jaw .proper beyond `such offset is in line with the jawv proper of vmember 26 so .that in closed or caging positions, such aligned jaws can squarely engage caging pins v23 and 48, to be described. between them.

The movement of gears 42 and 43 is accomplished by rotating a knob 49 (see Figs. 1 and 2) which is in veasy reach of the pilot near the face ofthe. instrument. Knob 49 is on the rear end 4of a shaft 50 which extends forward and is geared through gears 52, .and 53 to gear 43. These -gears are rotatively secured in proper po sition inthe caging head, 28. In order that the caging head and` mechanism may be readily removed from the instrument, shaftl 56 may be disconnected at points'54 or 55 or both by means of the screw fastenings shown in Fig. 2. The shaft also 'includes a double bow spring resillent section at 56 which is so biased -as to tend to shorten the shaftl and which serves normally to hold a lock pin 51 into a locking s'lotat 51' in the casing structure part 58. When the pilot desires to rotate sharft 50 to uncage or cage the d gyro when the pin 51 is in its .slot 51', he iirst pulls the knob 49 toward him or to the rear to disengage pin 51 from its locking slot and then rotates the shaft. If the knob is released when pin 51 is in alignment with its slot, spring 56 draws -the shaft forward to relock the shaft from rotation. The important locking position of shaft 5.0 is at the caged position of the jaw members. The gear ratio may be such that movement of the caging device over its cornplete range requires less than one .revolution of the gear 5|. In the full open or uncaged position of the jaw members, tabs .64 on the back side of the jaw portions engage in wedging relation with back stop surfaces (see Fig. 1) on the instrument Vframework and serve to secure the jaws in open position. In the caged position the jaws are against the caging pins 23 and 48 which also serve as stops. It will be noted that the structure of shaft 50 and spring 56 is such as to allow a slight torsional resiliency of the shaft structure between gear 5| and lock 51. I preferably arrange matters so that in turning the shaft 50 to caging position, it is necessary to twist the shaft 59 very slightly an additional amount in the same direction to engage the lock pin 51 in its slot 51' after the jaws have come to their stopped positions. The same expedientl may be used in the open position. By reason of this feature there is a slight torsional strain on shaft 50 when locked, urging` slots 38 and 39 just beyond a jog 60 in such slots. The shape of this jog in relation to the direction of movement of the pins therein is made such as to tend to lock the jaws in a closed position unless released by movement of the crank arms. That is, attempt to move the jaws apart by pulling on the arms rather than Yby movement of the crank pins is resisted because the pins are substantially in line with the pivot points of their crank arms andthe point of contact between the pins and the engaging shoulder of the slot. Thus in Fig. 4, pin 36 is substantially in line with the axis of rotation of gear 42 and the shoulder point of -contact at 6|, and any attempt to move pin 36 by movement o f jaw member 26 upward produces a force on the crank comprising arm 40 and pin 36 in a dead-center direction towards the axis of rotation of gear 42. Hence this feature is important and desirable in preventingan unintentional uncaging movement of the .parts due to vibration. However, an uncaging operation by yapplication of the movement force through the crank arm rather than through the jaw member encounters no opposition of this nature.

When the jaws approach caging position, a .pin 62 on jaw member 26 (see Fig. 3) engages V Fig. "1.

.1. shell toprovide a tight lit.

a sloping surface 63on the part 48 of jawinem-y lber 21 and prevents any tendency for the jaw parts to spread apart axially `and producentl guiding, lbracing action betweeny the jawmem` bers at this point, which is desirable from the 1 standpoint of rigidity and ,good alignment Voi" parts and in relieving the bearings/of the jaw members from lateral strain.

The oaging pin 48 extends outwardly from the side of gimbal ring I2, asshown in Figyl, into .1. Inag'yroinstrument,a supporting framework, a gi'mbal ring trunnicned in said framelwork on, a foreeandeaftaxis, a gyro rotor bear-v ing @frame pivoted in said gimbalfring on a transverse. axis, said vgimbal ring and' rotor bearing framefhaving caging pins extending therethe path of movement of jaws. 26 andl '21. Such L- pin is perpendicular to the axis lof rotation Lof such girnbal and may rotate about such axisin a plane'perpendicular to such axis withinl an arc,

limited Vby the open position of the caging jaws. When the caging jaws yare closed, the pin 48and hence gimbal ringI2 are brought to the central position-.represented in Fig. 1. The caging pin 23 which serves also to move the horizontal bar from beyond the'path of rotation of the gimbal them to central positions to cage said gyro comprising apair of caging members pivoted for rotationabout theifore-and-aft axis outside of said i gimbal ringysaidmembers having radial arm parts and jawrriarts extending in the direction of said instrumentfiparallel to said foreeand-aft axis outside of said""gimbal ring, said caging lmembers having closed `positions in which their jawvparts grasp said `caging lpins between them with such ring and may thus have a variety off ,Y

positions relative to thecasing of thelinstrument. It also extends into the path of movement of the' caging jaws, and when they are closed will be brought to the `central position represented at the same time the gimbal ring is centered. Thus the `gyro is caged or its two axes of movement relative to the casing are Ibrought to the central position shown in Fig. 1, whenever desired and for any reason. Fig. 3 represents a somewhat distorted exploded view of the caging features in caged position. In this View the inside of the gimbal ring I2 lis towards the observer.

It will be apparent that during a caging operation the caging jaws are necessarily brought into instrument.

with "the cagingpins in their central positions and having open positions which allow for normal' freedom of movement of such cagingvpins ringfperpendicular tothefore-and-aft axis, and `means 'for engaging said caging pins and moving from their central positions,A operating means for simultaneously. moving both coaging members from open toclosed positions-and vice `versa and a supporting s truotureifor said cagingl members and operating means removably secured to said frameworlqahd removable therefrom without disturbingany ofth operating parts of said 2. In an articialhorizon instrument for airplanes, a gyro,-a `Vgirnbal ring mounting therefor having its major axis trunnions fore and aft of the airplane and minor axis trunnions lateral, and means for cagingv said'gyro in a central' position corresponding L'to' its normal position when the airplane is in-Ls'traight level ight comprisl ing a pair of cagin'g-mmbers having radial arm Contact with the caging pins and the pins forced l to caging position rather gradually' because due to the natureof the driving transmission, the cagingV jaws cannot be moved abruptly nor can an undesirable, excessive amount of `force be applied through the thumb piece 49 by'turning with the thumb and fingers. This is desirable to prevent damage to thebearingsof the" gyroscope because anl abrupt displacement of the axis of a spinning gyro can produce an enormous strain on the bearings.

The caging head 28 which carries all of; the

. 'aging parts except those associated with the left V'.-Qe'ndzofshaft 50 in Fig. 1 is secured to the forwardend of the instrument framework part VI3 by three screws, two of which are shown at 12, Such screws enter through the `holes 13.1'l ,Wn in Fig. 2. The caging head may be moiintedin place either with or without the cylindrical-shell enclosure part 83 (see Fig. l).

" When assembled with the cylindrical shell, the

rim of the casing-head engages the. end of the The shell may be left off i'or test purposes. Thus it is seen that thecaging device may be quickly' removed or added to the gyro without .disturbance of other essential parts. Itwill be evident from Figs. 1

and 2 that the gear 5I is housed in aportion oi' head 2B which extends beyond the edge of the circular cover part thereof so that the shaft 5U is outside of the casing `8i! and hence is accessible for coupling and uncoupling.

What I claim as new and desire to secure by Letters Patent of the United States is:

partspivoted for rotation about the major axis of said gyro outside of the gimbal ring and having jaw parts extending parallel to said axis outsidethe gimbal ringto approximately the minor axis, a caging pin extending from said gmbal into the path of rotation of said jaws, and a crank arm from the minor axis gyro part having I its crank pin extending through anfarc-shaped.

slot in said gimbal into thepath of rotation of' said jaws,.both of said pins being engaged between said jaws with the gyro` in theaforesaid y central position when the jaws are rotated to y caging position, -a cage head for rotativelysupporting said caging members, means carried by said cage head forv simultaneously moving said caging members between open and closed posi- Y tions and vice versa, said cage head and theparts supported and carried-thereby being removable from said instrument as aiunit Without disturb'- ing anyof the `operating parts of said instrumental 43. A caging head unit for removable mounting.' lwith respect to an artificial horizon gyro instru-i "ment comprising a' supporting structure formingjlr `a circular front cover for such an instrument, a5?

,. Nid

pair of arms pivotally mounted on the insidev center axis of said-structure, said arms having.

radial slotted* parts 4and outencaging jaw parts extending` axially away from 'saidstructura said arms being rotatable in oppositevdirectionsa `from a position where the jaws are substantially-closed throughv angles of the order of 90 degrees tof'fan operr position, a pair of similar sized interrieshed gears pivoted to said structure, cranldi arms secured'to said gears" with crank pins engaging the slots in the radial parts of said arms and arranged to move said arms between open and closed positions when said gears are rotated, said structure having a part extending beyond the edge of the front cover` circle thereof, a shaft having a bearing in said extended part and extending out of the rear face thereof and gearing between said shaft and one of said intermeshed gears. A

4. In a caging mechanism for gyro instruments, a supporting structure having a pair of caging'arms pivoted thereto about the same axis, said arms containing radially extending slots having jogs therein, a pair of similar sized intermeshed gears rotatively mounted on said supporting structure on axes parallel to and equally distant from the axis of rotation of said caging arms, egual length crank arms secured to said gears having crank pins extending into the slots of said caging arms, means for simultaneously rotating said gears to cause the caging arms to rotate between open and closed positions, the arl rangement being such that in moving said arms from open to closed positions the crank pins rst move outwardly and then inwardly in said slots and such that in the closed positions of said caging arms the crank pins have thus moved inwardly just beyond the Jogs in said slots, the jog in said slots being so shaped that shouldered surfaces of such slots rest against the crank pins at points subtantially in line with the crank pins and the axis of rotation of their crank arms when the caging arms are in the closed position, whereby movement of said caging arms from such position except through driving action of the crank pins is resisted. l

B. In combination with a gyro instrument having a supporting framework with a gimbal ring trunnioned for rotation within said framework along a given axis and with bearings for saidv removably secured to one end of said framework and supporting caging mechanism in operative. relation to said instrument and a caging turn `knob extending from the other end of said framework, said knob'l being removably connected in operating relation with said mechanism through a shaft extending parallel with the axis of rotation of said gimbal ring and outside the range of rotation thereof, said shaft having a transversely extending locking pin adapted to t into a locking slot in the knob end of the framework and to be released from said slot to enable the shaft to be turned by pulling on the knob, said shaft having atorque transmitting flexible section between the twe ends ofl thel framework which tends to shorten the shaft and thereby' to pull the locking pin into its locking slot when the rotative position of the shaft permits, said section permitting the knob end of said shaft to be pulled endwise to unlock the same.

SAMUEL GABRIELSON. 

